1. Field of the Invention
The present invention is directed to a postage meter machine with a chip card write/read unit, of the type wherein a microprocessor controls a printing procedure dependent on a chip card which is currently inserted in the write/read unit. The present invention is also directed to a method for operating such a postage meter machine.
2. Description of the Prior Art
It is known to keep track of accounting-specific data about cost centers in postage meter machines. The purpose of the cost center concept is to introduce transparency into the accounting of devices that are used by different users. The term "cost center" means a non-volatile memory area provided for department-by-department accounting or booking of usage activity. Each cost center has a number and/or name allocated to it via which the aforementioned memory area is selected. The business entity associated with a cost center is ultimately responsible for the cost (charge) for postage or shipping fees incurred by personnel who use the postage meter machine who are employed by the business entity.
Modern postage meter machines such as, for example, the thermal transfer postage meter machine disclosed by U.S. Pat. No. 4,746,234 utilize fully electronic digital printer devices. It is thus fundamentally possible to print arbitrary texts and special characters in the postage stamp printing area and to print an arbitrary advertizing slogan or one allocated to a cost center. For example, the postage meter machine T1000 of Francotyp-Postalia AG & Co. (Postalia, Inc. in the United States) has a microprocessor that is surrounded by a secured housing having an opening for the delivery of a letter. Given delivery of a letter, a mechanical letter sensor (microswitch) communicates a print request signal to the microprocessor. The franking imprint contains a previously entered and stored postal information for dispatching the letter.
It is also known to store data specific to cost centers on chip cards in order to make the user-specific information mobile (portable) and to avoid an intentional misuse of other cost centers. U.S. Pat. No. 5,490,077 discloses a data entry with chip cards for the aforementioned thermal transfer postage meter machine. One of the chip cards loads new data into the postage meter machine, and a set of further chip cards allows a setting of correspondingly stored data to be undertaken by plugging in a chip card. Loading data and setting the postage meter machine are thus possible in an easier and faster manner than via a keyboard input. The keyboard of the postage meter machine remains small and surveyable because no additional keys are required in order to load or set additional functions. A plug-in slot of a chip card write/read unit, in which the respective chip card is to be plugged by the customer within a time window, is located on the back side of the postage meter machine. Due to the lack of direct visual contact, an unpracticed user often does not always succeed in inserting the required chip cards in immediate succession, which then leads to unwanted delays. The plug-in slot of a chip card write/read unit is only easily accessible when the user bends over the machine. The problems in producing visual contact increase given larger machines. The user often has a number of other chip cards that can be plugged in. One chip card type (size format), for example telephone cards, credit cards and the like, can be physically inserted into the postage meter machine but will not be accepted. Without visual contact, however, the error is not always immediately obvious. The postage meter machine only works with relatively expensive chip cards that are themselves equipped with a microprocessor (smart card) and are thus able to check whether the postage meter machine communicates a valid data word to the chip card before an answer is sent to the postage meter machine. When, however, no answer or user identification ensues, this is registered as an error in the postage meter machine and is displayed before a request to remove the chip card is displayed in the display. To register an erroneously inserted telephone card as attempted fraud, however, would not be reasonable given the not unlikely occurrence of an "innocent" mistake.
German OS 196 05 015 discloses an embodiment for a printer device (JetMail.RTM.) that, given a non-horizontal, approximately vertical letter transport, implements a franking imprint with an ink jet print head stationarily arranged in a recess behind a guide plate. For recognizing the start (leading edge) of a letter, a print sensor is arranged shortly before the recess for the ink jet print head and collaborates with an incremental sensor. The letter transport is free of slippage due to pressure elements arranged on the conveyor belt, and the incremental sensor signal derived during the transport has a positive influence on the quality of the print image. Given such a postage meter machine exhibiting larger dimensions, however, a chip card write/read unit would have to be arranged and operated such that sequentially pluggable chip cards can be unproblematically used.
As an alternate way for solving the further problem that there is only limited memory capacity available on a chip card, U.S. Pat. No. 4,802,218 discloses that a number of chip cards be simultaneously employed, these being plugged into a number of write/read units. In addition to a user chip card for the recrediting and debiting. whereby the postage fee value is subtracted from the credit, a master card and a further rate chip card with a stored postage fee table are simultaneously plugged in. By accessing a postage fee table, a postage fee value can be determined according to the input weight and shipping destination without loading an entire table into the machine. Since, however, a respective write/read unit is required for every chip card, the apparatus becomes too large and expensive. Moreover, a separate reloading terminal is required in order to replenish the credit in the user chip card, with the master card providing the authorization for this reloading function. A supervisor card has access to all master cards. Various security levels are accessible by appertaining key codes. Such a system with a number of slots for chip cards is very complex overall.
German OS 195 16 429 discloses a method for an access authorization to a secured machine or circuit with card-like master elements that make card-like authorization elements perceptible as valid. Such card-like authorization elements that have been validated later allow access to the secured machine or circuit without the user having the master element in his or her possession. Further authorization elements also can be confirmed as valid. The authorization procedure includes an information exchange between a higher-ranking master element and a lower-ranking authorization element or master element, and an electronic lock of the secured machine or circuit. Specific customer wishes, however, can not be taken into consideration because all cards generated in this way are technologically and functionally identical and merely serve the purpose of distributing access authorizations of a hierarchically ordered administration of the secured machine or circuit.
The employment of a chip card for access authorization in different hierarchy levels as well is known. It is likewise known to require a PIN or password input in various security levels for insuring the authenticity of a user. It is disadvantageous, however, that there is no security procedure that can recognize a group of security requests which are individually adapted.
The chip cards are usually initialized by the chip card manufacturer and the postage meter machine manufacturer. It is somewhat complicated, however, for the postage meter machine manufacturer to take specific customer wishes into consideration. There is the necessity for the user of the postage meter machine to inform the manufacturer of his customer wishes that relate to a specific input function by chip card. Until the user has been sent an correspondingly initialized chip card, the postage meter machine can continue to be set for the specific input function only via the postage meter machine keyboard.
Inexpensive chip cards often only have high limited memory capacity. This memory capacity is neither sufficient for accepting the full scope of cost center-specific data nor for storing additional security data.